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Title: High-pressure compressibility and vibrational properties of (Ca,Mn)CO 3

Knowledge of potential carbon carriers such as carbonates is critical for our understanding of the deep-carbon cycle and related geological processes within the planet. Here we investigated the high-pressure behavior of (Ca,Mn)CO 3 up to 75 GPa by synchrotron single-crystal X-ray diffraction, laser Raman spectroscopy, and theoretical calculations. MnCO 3-rich carbonate underwent a structural phase transition from the CaCO 3-I structure into the CaCO 3-VI structure at 45–48 GPa, while CaCO 3-rich carbonate transformed into CaCO 3-III and CaCO 3-VI at approximately 2 and 15 GPa, respectively. The equation of state and vibrational properties of MnCO 3-rich and CaCO 3-rich carbonates changed dramatically across the phase transition. The CaCO 3-VI-structured CaCO 3-rich and MnCO 3-rich carbonates were stable at room temperature up to at least 53 and 75 GPa, respectively. In conclusion, the addition of smaller cations (e.g., Mn 2+, Mg 2+, and Fe 2+) can enlarge the stability field of the CaCO 3-I phase as well as increase the pressure of the structural transition into the CaCO 3-VI phase.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [5]
  1. Stanford Univ., Stanford, CA (United States)
  2. Univ. Claude Bernard Lyon 1, Lyon Cedex (France)
  3. Chinese Academy of Sciences, Guizhou (China)
  4. Univ. of Hawai'i at Manoa, Honolulu, HI (United States)
  5. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
American Mineralogist
Additional Journal Information:
Journal Volume: 101; Journal Issue: 12; Journal ID: ISSN 0003-004X
Publisher:
Mineralogical Society of America
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; carbonate; X-ray diffraction; raman spectroscopy; high pressure
OSTI Identifier:
1360964